1. Field of the Invention
The present invention relates to an apparatus for the determination of the respiratory passageways resistance, including a flow resistance in the breathing or respiratory flow passageway, whose resistance value is periodically varied by means of a frequency which lies above the breathing frequency, and including as well a pressure and/or, as occasioned, a flow measurement gauge.
2. Discussion of the Prior Art
In known apparatus of this type (for example German Published Specification No. 1,029,526, in addition to the therein referred state of the art) there are provided two flow resistance in the respiratory passageway, of which one (auxiliary resistance) may be periodically suddenly connected to the other by means of a valve or shutter, and again disconnected therefrom. In the periodic square-wave shaped variation of the flow resistance, there may then be measured for one the pressure drop p.sub.z thereacross at the obtained total resistance W at a therewith connected auxiliary resistance, and for the other the pressure drop p.sub.o thereacross at the obtained residual resistance W.sub.2 at a disconnected auxiliary resistance. From the resistance W and W.sub.2, as well as the measured differential pressures p.sub.z, respectively p.sub.o, there is then calculated the respiratory flow resistance W.sub.i pursuant to the relationship ##EQU1##
The respiratory passageway resistances which are obtained in accordance with the known measuring principles, however, are not sufficiently exact.